This invention relates to an orthodontic bracket for receiving and gripping an orthodontic arch wire.
Generally, orthodontics is a field of dentistry in which the position of the teeth are physically moved relative to one another and relative to the maxilla and mandible, such that after treatment the teeth are in proper relation to one another and to the facial skeletal structure of the patient. Treatment begins by the orthodontist examining the patient's mouth, both visually and radiographically, so as to determine the existing positions of the teeth and the structure of the maxilla and mandible. The orthodontist then plans a course of treatment to selectively move certain of the teeth so that after a period of active orthodontic treatment, the teeth will be disposed in proper positional relationship relative to one another and relative to the patient's facial skeletal structure. A variety of appliances are available for tipping the teeth, rotating them about a longitudinal axis of the tooth, or moving the teeth in posterior, anterior, buccal, or lingual direction. In addition, teeth may be expanded, contracted, intruded, torqued, or de-rotated, as decided by the treating orthodontist.
It is conventional to use a so-called arch wire to interconnect various teeth of the patient's upper arch or lower arch so as to apply desired forces to selected of the teeth so as to properly position these selected teeth in different stages of treatment. Typically, the arch wire consists of a relatively stiff but flexible wire of a suitable stainless steel or the like material which is carried by tubes and/or brackets on either the outside (buccal) or the inside (lingual) sides of the teeth, with the tubes and/or the brackets being secured to pads which in turn are bonded to the faces of the teeth. Forces can be applied to the teeth by selectively fixing or securing the wires to the tubes or to the pads.
In certain prior art bracket systems, the archwires are secured to the brackets bonded to the teeth by means of ligature wires or elastomeric ties which are wrapped around the archwire and the bracket. However, the installation of such ligature wires is difficult and time consuming and may not grip the archwire as securely as desired.
An archwire is oftentimes fixed by brackets to a desired number of teeth in a patient's arch. If certain of these teeth are out of a desired alignment with respect to one or with respect to a final position, it is possible to apply an expansive or compressive force on one or more desired teeth by deflecting the wire from its desired path and by securing the delected arch wire to the desired teeth so as to expand (i.e., to move the teeth bucally or outwardly) or to contract (i.e., to move the teeth lingually). However, this not only requires that archwire to be securely fastened to the teeth to be moved, but also to adjacent teeth which serve to anchor the archwire.
Of course, after the teeth have moved an incremental amount, the force applied by the archwire relaxes and thus requires periodic adjustment. However, in practice, the above-described ligature wires and elastomeric ties used to secure the arch wires may not grip the archwire as securely as desired, and are difficult to remove and re-apply. Elastomeric ties tend to creep and thus loose their tension.
A variety of brackets and spring clips are known for securing the arch wire to the brackets and for applying forces in a desired direction to the bracket and then to the teeth. Reference may be made to such U.S. Pat. Nos. as 3,128,553, 3,854,207, 3,871,096, 3,959,880, 4,023,274, and 4,551,094, which disclose various brackets having arch wire retention clips. Reference may also be made to U.S. Pat. Nos. 3,959,880 and 4,547,153, which disclose various clamps, clips, and pads used in conjunction with arch wires. Still further, resilient retaining members are disclosed in U.S. Pat. Nos. 4,260,375 and 4,492,573.
However, none of these prior art patents have made use of a bracket of the structure herein described which retains and increases the effect of the arch wire and allows conversion from one wire slot system to another.